#/* * TC-11 DECtape driver */#include "../h/param.h"#include "../h/conf.h"#include "../h/buf.h"#include "../h/dir.h"#include "../h/user.h"struct device {	int	tccsr;	union wb {		int	w;		char	b[2];	} tccm;	int	tcwc;	int	tcba;	int	tcdt;};struct	buf	tctab;char	tcper[8];#define	TCADDR	((struct device *) 0177340)#define	NTCBLK	578#define	TAPERR	0100000#define	TREV	04000#define	READY	0200#define	IENABLE	0100#define	UPS	0200#define	ENDZ	0100000#define	BLKM	02000#define	ILGOP	010000#define	SELERR	04000#define	SAT	0#define	RNUM	02#define	RDATA	04#define	SST	010#define	WDATA	014#define	GO	01#define	SFORW	1#define	SREV	2#define	SIO	3tcclose(dev){	bflush(dev);	tcper[dev&07] = 0;}tcstrategy(bp)register struct buf *bp;{	if(bp->b_flags&B_PHYS)		mapalloc(bp);	bp->b_resid = 0;	if(bp->b_blkno >= NTCBLK || tcper[minor(bp->b_dev)&07]) {		bp->b_flags |= B_ERROR;		iodone(bp);		return;	}	bp->av_forw = 0;	spl6();	if (tctab.b_actf==0)		tctab.b_actf = bp;	else		tctab.b_actl->av_forw = bp;	tctab.b_actl = bp;	if (tctab.b_active==0)		tcstart();	spl0();}tcstart(){	register struct buf *bp;	register int com;	register union wb *tccmp;loop:	tccmp = &TCADDR->tccm;	if ((bp = tctab.b_actf) == 0)		return;	if(tcper[minor(bp->b_dev)&07]) {		if((tctab.b_actf = bp->av_forw) == 0)			tccmp->b[0] = SAT|GO;		bp->b_flags |= B_ERROR;		iodone(bp);		goto loop;	}	if ((tccmp->b[1]&07) != minor(bp->b_dev))		tccmp->b[0] = SAT|GO;	tctab.b_errcnt = 20;	tctab.b_active = SFORW;	com = (minor(bp->b_dev)<<8) | IENABLE|RNUM|GO;	if ((TCADDR->tccsr & UPS) == 0) {		com |= TREV;		tctab.b_active = SREV;	}	tccmp->w = com;}tcintr(){	register struct buf *bp;	register union wb *tccmp;	register int *tcdtp;	tccmp = &TCADDR->tccm;	tcdtp = &TCADDR->tccsr;	bp = tctab.b_actf;	if (tccmp->w&TAPERR) {		if((*tcdtp&(ENDZ|BLKM)) == 0)			deverror(bp, *tcdtp, 0);		if(*tcdtp & (ILGOP|SELERR)) {			tcper[bp->b_dev&07]++;			tctab.b_errcnt = 0;		}		tccmp->w &= ~TAPERR;		if (--tctab.b_errcnt == 0) {			bp->b_flags |= B_ERROR;			goto done;		}		if (tccmp->w&TREV) {		setforw:			tctab.b_active = SFORW;			tccmp->w &= ~TREV;		} else {		setback:			tctab.b_active = SREV;			tccmp->w |= TREV;		}		tccmp->b[0] = IENABLE|RNUM|GO;		return;	}	tcdtp = &TCADDR->tcdt;	switch (tctab.b_active) {	case SIO:	done:		tctab.b_active = 0;		if (tctab.b_actf = bp->av_forw)			tcstart();		else			TCADDR->tccm.b[0] = SAT|GO;		iodone(bp);		return;	case SFORW:		if (*tcdtp > bp->b_blkno)			goto setback;		if (*tcdtp < bp->b_blkno)			goto setforw;		*--tcdtp = (int)bp->b_un.b_addr;	/* core address */		*--tcdtp = -(bp->b_bcount>>1);		tccmp->b[0] = ((bp->b_xmem & 03) << 4) | IENABLE|GO		    | (bp->b_flags&B_READ?RDATA:WDATA);		tctab.b_active = SIO;		return;	case SREV:		if (*tcdtp+3 > bp->b_blkno)			goto setback;		goto setforw;	}}